Russian President Vladimir Putin watches an opening ceremony of the second leg of the Eastern Siberia - Pacific Ocean (ESPO) oil pipeline through a live video link from the Novo-Ogaryovo residence outside

MOSCOW — The upper chamber of Parliament on Wednesday unanimously approved a bill to ban adoptions of Russian children by U.S. citizens, sending the measure to President Vladimir Putin, who has voiced support but not yet said if he will sign it.

Enactment of the adoption ban, which was developed in retaliation for an U.S. law punishing Russians accused of violating human rights, would be the most severe blow yet to relations between Russia and the United States in a year marked by a series of setbacks.

The vote in the Federal Council was 143-0, with 43 senators absent. By law, Putin has two weeks to act on the bill, but a decision is expected sooner. The bill calls for the ban to take effect Tuesday.

The U.S. ambassador, Michael A. McFaul, who criticized the bill after the lower house passed it last week, posted a more restrained comment on Twitter on Wednesday noting the fierce disagreement that has erupted within Russian government and society.

"I agree with hundreds of thousands of Russians who want children removed from political debate," McFaul wrote.

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Since Putin returned to the presidency in May, Russian officials have used a juggernaut of legislation and executive decisions to curtail U.S. influence and involvement in Russia, undoing partnerships that began after the fall of the Soviet Union.

In September, the Kremlin ordered the U.S. Agency for International Development to cease operations here, shutting a wide portfolio of public health, civil society and other initiatives. And officials announced plans to terminate a joint effort to dismantle nuclear, chemical and other nonconventional weapons known as the Nunn-Lugar agreement.

Russia also passed a law requiring nonprofit groups that get financing from abroad to register as "foreign agents," sharply limiting the ability of the United States to work with good-government groups, and another law broadening the definition of treason to include "providing financial, technical, advisory or other assistance to a foreign state or international organization."

The adoption ban, however, is the first step to take direct aim at the American public and would effectively undo a bilateral agreement on international adoptions that took effect Nov. 1.

About 1,000 Russian children were adopted by U.S. parents in 2011, more than any other country, and more than 45,000 such children have been adopted by U.S. parents since 1999.